We commonly use this like, "She is really down to earth" or "She is a down to earth person." The inference is that a person's "head is [not] in the clouds;" they are mentally "grounded" or "on earth" as opposed to in the clouds, sky or in space. The humble concept of "down to earth" is the idea that you are not "above" everyone else (i.e. on a pedestal), you are "grounded" or stay on the same level as others. I threw several extra phrases in for additional context and learning. I hope it helps. Take care!

If someone is "down to earth", that means that they are not arrogant or egotistical. Someone who is humble, or someone who is practical or realistic. Typically it's a compliment! :)

https://www.italki.com/question/439944 Honestly I still don't feel when to use this phrase even after having read all the opinions...

It doesn't really mean anything, even though many people like to use this phrase. It means someone who is honest and calm, doesn't cause drama or behave in a pretentious way.